1. Field of the Invention
This invention relates to replacement windows and more particularly to replacement windows having built-in intrusion alarm systems.
2. Description of the Related Art
Intrusion alarms for windows and doors are typically designed so that window or door movement from a closed position actuates the alarm. Usually a switch is closed by the movement to initiate the alarm as disclosed in U.S. Pat. No. 3,742,479 to Williams. This arrangement requires, in the case of windows, disabling the alarm before opening the window for ventilation purposes or for cleaning. When such windows are opened for ventilation, there is no alarm protection against intruders.
In some prior art proposals, after a window is opened and an alarm is sounded, reclosing the window discontinues the alarm. When a potential intruder opens such a window the alarm may quickly be shut off by the intruder closing the window. In such circumstances a prowler might not be frightened away by the alarm and the prowler's presence not adequately signalled.
Some window alarms are mounted on the window frame. See, for example, U.S. Pat. No. 4,472,709 to White and U.S. Pat. No. 3,378,830 to Patrick. This can result in an unsightly window and may permit tampering with the exposed alarm system by an intruder. Some alarms are constructed to be installed within an existing door or window. For example, see U.S. Pat. No. 3,768,087. Here an installation job is required to place the alarm and tools are necessary to remove the alarm for maintenance or repair.
The present invention provides a new and improved replacement window having an intrusion alarm system enabling the window to be opened in such a way that an alarm is not triggered yet intruders can not enter.